U.S. patent number 7,017,763 [Application Number 10/625,508] was granted by the patent office on 2006-03-28 for base having a flexible vacuum area.
This patent grant is currently assigned to Graham Packaging Company, L.P.. Invention is credited to Paul V. Kelley.
United States Patent |
7,017,763 |
Kelley |
March 28, 2006 |
Base having a flexible vacuum area
Abstract
A non-round base structure for a hot-fill plastic container
provides the container with enhanced structural integrity. The base
structure is roughly rectangular and is composed of a flexible
vacuum absorbing area and a bearing edge which support the
container in an upright position. The flexible vacuum absorbing
area abates with a central ellipse shaped push-up, which is a
concave surface. A series of ribs with an outward facing rounded
edges are fashioned on the concave surface. The ribs extend
outwardly from the center of the ellipse. The disclosed base
structure enables the container to withstand the various forces
encountered in filling, cooling and handling.
Inventors: |
Kelley; Paul V. (Thurmont,
MD) |
Assignee: |
Graham Packaging Company, L.P.
(York, PA)
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Family
ID: |
30773525 |
Appl.
No.: |
10/625,508 |
Filed: |
July 24, 2003 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20040164045 A1 |
Aug 26, 2004 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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60398021 |
Jul 24, 2002 |
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Current U.S.
Class: |
215/383; 215/381;
220/606; 220/609 |
Current CPC
Class: |
B65D
1/0223 (20130101); B65D 1/0276 (20130101); B65D
2203/02 (20130101); B65D 2501/0036 (20130101); B65D
2501/0081 (20130101) |
Current International
Class: |
B65D
1/42 (20060101) |
Field of
Search: |
;215/373,375,381
;220/606,608,609 ;D9/520 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1354801 |
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Oct 2003 |
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EP |
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408301253 |
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Nov 1996 |
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JP |
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2001315741 |
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Nov 2001 |
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JP |
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WO 97/34808 |
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Sep 1997 |
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WO |
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Primary Examiner: Weaver; Sue A.
Attorney, Agent or Firm: Venable Burdett; James R. Kaminski;
Jeffri A.
Claims
What is claimed is:
1. A non-round base structure for a blow-molded container having
rectangular sidewalls, comprising: a support heel comprising a
bearing edge and a flexible vacuum absorbing area having an outer
portion and a roughly ellipsoidal inner portion, said outer portion
merging with the container rectangular sidewalls and said inner
portion merging with a central concave wall; the central concave
wall having an apex and a plurality of ribs extending outward from
the apex along the concave wall, each rib having a rounded edge
extending outward from the interior of the container; and whereby
the vacuum absorbing area and ribs cooperate to enhance the
structural integrity of the container by rigidifying said central
concave wall and by providing multiple paths of interengageable
surfaces that make it difficult for deflection, once initiated, to
propagate to undesired distortion.
2. The non-round base structure for a blow-molded container of
claim 1, wherein the outer portion is roughly ellipsoidal.
3. The non-round base structure for a blow-molded container of
claim 2, wherein the flexible vacuum absorbing area enhances the
support bearing edge upon container filling.
4. The non-round base structure for a blow-molded container of
claim 2, wherein the flexible area defines a cord length between
the inner portion and the outer portion, and the cord length is no
more than about 25% longer at its longest point than at its
shortest point.
5. The base structure according to claim 1, wherein the ribs form a
substantially symmetric array.
6. The base structure according to claim 5, wherein the array is
substantially star-shaped.
7. The base structure according to claim 1, wherein there are at
least about six ribs.
8. The base structure of claim 1, wherein the vacuum flexible area
partially surrounds the area defined by the concave wall.
9. The base structure of claim 8, wherein the vacuum flexible area
is separated into two roughly symmetrical areas by recessed
structures on opposite sides of the concave wall.
10. A base structure according to claim 1, wherein said base
structure comprises polyethylene terephthalate.
11. A non-round base structure for a blow-molded container having
rectangular sidewalls, comprising: a support heel comprising a
bearing edge and a flexible vacuum absorbing area having a roughly
rectangular outer portion and a roughly ellipsoidal inner portion,
said outer portion merging with the container rectangular sidewalls
and said inner portion merging with a central concave wall; the
central concave wall having an apex and a plurality of ribs
extending outward from the apex along the concave wall, each rib
having a rounded edge extending outward from the interior of the
container; and whereby the vacuum absorbing area and ribs cooperate
to enhance the structural integrity of the container by rigidifying
said central concave wall and by providing multiple paths of
interengageable surfaces that make it difficult for deflection,
once initiated, to propagate to undesired distortion.
12. The non-round base structure for a blow-molded container of
claim 11, wherein the flexible vacuum absorbing area enhances the
support bearing edge upon container filling.
13. The non-round base structure for a blow-molded container of
claim 11, wherein the flexible area defines a cord length between
the inner portion and the outer portion, and the cord length is no
more than about 25% longer at its longest point than at its
shortest point.
14. The base structure according to claim 11, wherein the ribs form
a substantially star-shaped, symmetric array.
15. The base structure of claim 11, wherein the vacuum flexible
area partially surrounds the area defined by the concave wall.
16. The base structure of claim 15, wherein the vacuum flexible
area is separated into two roughly symmetrical areas by recessed
structures on opposite sides of the concave wall.
17. A base structure according to claim 11, wherein said base
structure comprises polyethylene terephthalate.
18. A non-round base structure for a blow-molded container having
rectangular sidewalls, comprising: a support heel comprising a
bearing edge and a flexible vacuum absorbing area having a roughly
ellipsoidal outer portion and a roughly ellipsoidal inner portion,
said outer portion merging with the container rectangular sidewalls
and said inner portion merging with a central concave wall, wherein
the flexible vacuum absorbing area is adapted to enhance the
support bearing edge upon container filling and defines a cord
length between the inner portion and the outer portion that is no
more than about 25% longer at its longest point than at its
shortest point; the central concave wall having an apex and a
plurality of ribs extending outward from the apex along the concave
wall to form a substantially star-shaped symmetric array, each rib
having a rounded edge extending outward from the interior of the
container; and whereby the vacuum absorbing area and ribs cooperate
to enhance the structural integrity of the container by rigidifying
said central concave wall and by providing multiple paths of
interengageable surfaces that make it difficult for deflection,
once initiated, to propagate to undesired distortion.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority under 35 U.S.C. .sctn. 119(e)(1)
of provisional application No. 60/398,021, filed Jul. 24, 2002.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a blow-molded container
having a base structure which enhances the structural integrity of
the container, and more particularly to a non-round base structure
having a heel-push-up design.
2. Related Art
Many beverage products are sold to the consuming public in plastic
containers such as those that are shown in U.S. Pat. No. 5,005,716
(Eberle), U.S. Pat. No. 4,108,324 (Krishnakumar et al.), and U.S.
Pat. No. 4,134,510 (Chang). The design of plastic containers must
take into account the container's structural integrity, the
manufacturing cost to mass-produce the container, and the aesthetic
appearance of the container to the eye of the consumer.
A hot-fillable plastic beverage container must be structurally
sound to withstand various forces relating to the so-called
"hot-fill" process. Moreover, it must withstand rough handling
during transportation to the ultimate consumer. A "hot-fill"
process is the procedure by which containers are filled with a
beverage at a high temperature after which the containers are
capped. As the beverage cools within the container, stresses and
strains develop in the container due to changes in the volume of
the contents. Containers that store products under pressure, such
as carbonated beverages, also experience pressure changes due to
changes in ambient temperature. A commercially satisfactory
container structure must not only withstand these forces from a
structural viewpoint, but it must also present an aesthetically
pleasing appearance to the ultimate consumer.
The price of many products sold to the consuming public is affected
to an extent by the cost of packaging. With plastic beverage
containers, the cost of manufacturing a container is affected by
the cost of plastic composing the container. Therefore, if the
amount of plastic in a container can be reduced (i.e., a process
known as "light weighting"), the cost of manufacturing the
container can be reduced commensurately. However, in achieving this
goal it is known that the thinner the walls and base of the
container become, the greater the need is to utilize imaginative
designs to provide a container that is commercially acceptable.
The desire to decrease the amount of plastics used in a container
has resulted in the development of different techniques to design
containers that have structural integrity with minimal use of
plastic. It is known that the shape and location of structural
elements such as ribs, hinges, panels, and the like can affect the
container's overall structural integrity. While various structural
elements molded in the side panel and base structure can afford
structural integrity, they must also be visually appealing to the
consumer.
Krishnakumar et al ('324) illustrate a rounded container base
structure, which employs various structural elements molded into
the base that enhances structural integrity. This base design has a
series of radially extending ribs, which allow the base structure
to withstand a variety of applied forces and which minimize the use
of plastic.
Eberle ('716) discloses a round base structure having a central
concavity and a convex heel. The heel surrounds the concavity and
merges with the concavity and the container sidewall. A plurality
of hollow convex ribs, distributed in a symmetrical array,
interrupt the outer surface of the concavity and merge smoothly
therewith, each rib extending longitudinally in the direction of
the heel and downwardly from an inner portion of the concavity. The
wall of the bottom structure generally decreases in thickness
progressively from the innermost point of the concavity to the
sidewall. The structure allows the base to withstand the various
stresses and strains applied to the container and also minimizes
the use of plastic.
Chang ('510) shows a round base, which employs a series of
circumferential ribs in combination with radial ribs to provide the
desired degree of structural integrity. The radial ribs intersect
all of the circumferential ribs. The various ribs are solid.
The well known 1.75-liter Tropicana Twister.RTM. (a registered
trademark of Tropicana Products, Inc., 1001 13th Avenue, East
Bradenton, Fla. 33506) plastic beverage container has a rounded
heel/push-up base design with a very narrow heel surface which
functions as the horizontal bearing surface. However, the
1.75-liter Tropicana Twister plastic beverage container contains no
vacuum base flex area in its base.
Although the aforementioned containers and base structures may
function satisfactorily for their intended purposes, there remains
a continuing need for a blow-molded plastic container having a base
structure which enhances container structural integrity while
requiring a minimum use of plastic. Also, these base structures
need to be aesthetically pleasing and be capable of being
manufactured in conventional high-speed equipment.
BRIEF SUMMARY OF THE INVENTION
The substantially non-rounded base structure of the invention
incorporates a flexible vacuum absorbing area along with an
ellipsoid-shaped heel/push-up structure. The design allows for a
stable horizontal base and a capability to reduce the gram weight
of the container while enhancing performance of the containers
vacuum absorption capacity and/or broadens container design
possibilities.
The more conventional method has been to use a typical round bottle
heel/push up style. This causes the base to be heavier and also
less capable of flexing for vacuum absorption that makes it more
difficult to light weight the container.
The general function of the flexible vacuum absorbing area works by
creating a flex area between the substantially non-round (e.g.,
ellipsoid-shaped) push-up and heel radius of the bottle sidewall.
This area is relatively constant between the non-round
(ellipsoid-shaped) push-up and heel radius of the bottle sidewall.
In contrast, the conventional rounded base has a more dramatic
difference in the area from the corners of the container to the
centers. The cord lengths which define the flex area can vary in
length but preferably do not exceed a difference of more than about
twenty five percent. This difference allows the flex area in the
non-round push up to function more efficiently during cooling for
vacuum absorption and also creates a bearing edge for the bottle to
sit more stably than existing like structures.
The present invention provides a novel container base structure
which improves the overall structural integrity of the container
which, in addition, uses a minimum of plastic material. A further
object of the present invention is to provide a container base
structure which does not detract from the aesthetics of the
container even after it has been subject to various stresses and
strains associated with filling, transportation and handling. A
further object of the present invention is to provide a container
having an improved base structure, which affords manufacture by
high speed, automated equipment at a minimum of cost.
The base structure has a support heel, which has an inner and an
outer portion. The outer portion of the support heel merges with
the container sidewall. The inner portion of the support heel
merges with a central concave wall, the central concave wall being
surrounded by the annular support heel.
The central concave wall has a plurality of ribs. These ribs form a
symmetrical array. The specific number of these ribs can vary. The
ribs and concave surface cooperate to enhance the structural
integrity of the container base.
Preferably, the blow-molded container according to the present
invention may suitably comprise polyethylene terephthalate, which
is also known more commonly as PET. PET is a semi-crystalline
thermoplastic. Depending on its transformation state, PET can be
found in a totally "amorphous" or a "semi-crystalline" form. In the
latter case, its morphology is comprised of amorphous and
crystallized phases. In its amorphous state, PET's molecular chains
are not organized, sort of like a big ball of yarn. Conversely, in
its crystallized state, PET's molecular structure is a dense and
organized arrangement of molecular chains.
Further objectives and advantages, as well as the structure and
function of preferred embodiments will become apparent from a
consideration of the description, drawings, and examples.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing and other features and advantages of the invention
will become apparent from the following, more particular
description of a preferred embodiment of the invention, as
illustrated in the accompanying drawings wherein like reference
numbers generally indicate identical, functionally similar, and/or
structurally similar elements.
FIG. 1 shows a three-dimensional view of a rectangular container
with a ribbed vacuum side panel and the base structure of the
invention;
FIG. 2 shows an enlarged view of the base structure shown in FIG.
1;
FIG. 3 shows a planar view of the base structure shown in FIGS. 1
and 2, illustrating an ellipsoid shaped concave surface with a
symmetric array of ribs with cross sectional cuts 5--5 and 6--6
identified;
FIG. 4 shows a planar view of the base structure shown in FIGS. 1
and 2, illustrating an ellipsoid shaped concave surface with a
symmetric array of ribs;
FIG. 5 shows a cross section 5--5 of FIG. 3, with the shaded area
illustrating the relative thickness of the container wall;
FIG. 6 shows cross section 6--6 of FIG. 3, with the shaded area
illustrating the relative thickness of the container wall; and
FIG. 7 shows a planar view of the base structure where the flex
area is shown in stiple. The flex area typically does not exceed a
25% difference in cord length as measured from the inside edge to
the outside edge.
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the invention are discussed in detail below. In
describing embodiments, specific terminology is employed for the
sake of clarity. However, the invention is not intended to be
limited to the specific terminology so selected. While specific
exemplary embodiments are discussed, it should be understood that
this is done for illustration purposes only. A person skilled in
the relevant art will recognize that other components and
configurations can be used without parting from the spirit and
scope of the invention. All references cited herein are
incorporated by reference as if each had been individually
incorporated.
Referring now to the drawings, FIG. 1 illustrates a blow-molded
plastic non-round container (1) such as may be used in the sale of
juices and other non-carbonated beverages. The container has
rectangular sides. Such containers can typically be designed to
contain liquid volumes of 64 ounces, a gallon, or higher. The
container (1) has a neck (2) defining an opening allowing for
filling and pouring of a beverage. The neck (2) merges with the
rectangular sidewalls (20). The rectangular sidewalls (20) merge
with the non-round base structure (4) opposite the neck. The
container (1) is designed to receive a cap (not shown) to seal the
container and confine the beverage inside the container. While the
sidewalls as shown are rectangular, any substantially rectangular
shape including a square shape can be utilized. In such an
embodiment, the base would be shaped appropriately to merge with
the sidewall.
When used in hot-fill processing, the container is filled with a
beverage at an elevated temperature. The cap is then installed on
the container neck. As the temperature of the beverage and air
decreases to ambient temperatures, its volume decreases. The
container and its base structure must react to the reduction in
volume and accommodate the stresses and strains while remaining
structurally sound. Moreover, the base must also be capable of
withstanding various other forces, such as changes in internal
pressure with carbonated beverages, and the usual handling
forces.
The base structure of the present invention is shaped to withstand
these various forces. The base structure reduces the need for
plastic, yet still enhances the overall structural integrity of the
container. To this end, as seen in FIG. 3, for example, the base
structure has a substantially ellipsoidal shaped support heel (21).
The support heel (21) allows the container (1) to be supported
erect on a horizontal surface. The support heel (21) is rounded and
forms a continuous line of contact with a horizontal surface (not
shown). Included in the support heel structure are recessed
structures (27), which can enhance the horizontal stability of the
container (1) when placed on a flat surface.
The support heel (21) has an inner and an outer portion, (22) and
(23), respectively. The outer portion (23) merges with the
container's rectangular sidewalls (20). The inner portion (22) of
the annular support heel (21) has an upwardly inclined surface
(24), which merges with a central concave wall (25). The support
heel (21) can be flexible in the region between the inner portion
(22) and the outer portion (23). The support heel (21) can define a
cord length X, which extends in a substantially radial direction
between the inner portion (22) and the outer portion (23), as shown
in FIG. 4. Preferably, the cord length X does not change more by
more than about 25% as it extends around the base (4) of the
container (1). That is, the cord length at its longest point is
preferably no more than 1.25 times the cord length at its shortest
point. For example, as show in the embodiment of FIG. 4, the cord
length is X at its shortest point and 1.2 times X at its longest
point.
The central concave wall (25) is provided with integral molded
structural elements that provide the base (4) with sufficient
structural integrity to withstand the various forces acting on the
container (1). To this end, the central concave wall (25) has a
plurality of ribs (26), which extend from the center outward. The
ribs have a rounded edge (28), which extends outward relative to
the interior of the container. The ribs can form a symmetric array.
See, e.g., FIGS. 2 4 and 7.
As shown in FIGS. 2 4 and 7, the central concave wall (25) is
illustrated with an array of six ribs. However, a greater or fewer
number of ribs can be used so long as the function is achieved.
Containers having this base structure design can be produced in
commercial quantities with high-speed equipment.
All references cited in this specification are hereby incorporated
by reference. The discussion of the references herein is intended
merely to summarize the assertions made by their authors and no
admission is made that any reference constitutes prior art relevant
to patentability. Applicant reserves the right to challenge the
accuracy and pertinency of the cited references.
The embodiments illustrated and discussed in this specification are
intended only to teach those skilled in the art the best way known
to the inventors to make and use the invention. Nothing in this
specification should be considered as limiting the scope of the
present invention. All examples presented are representative and
non-limiting. The above-described embodiments of the invention may
be modified or varied, without departing from the invention, as
appreciated by those skilled in the art in light of the above
teachings. It is therefore to be understood that, within the scope
of the claims and their equivalents, the invention may be practiced
otherwise than as specifically described.
* * * * *